Meldungen

"Endlosschleifen im Kopf"

Beitrag zum Thema Ohrwurm in SWR2 vom 10. Dezember 2017:

"Jeder kennt sie, kaum einer mag sie: Ohrwürmer. Schon länger beschäftigen sich Psychologen und Mediziner mit dem Phänomen. Inzwischen weiß man, wie sie in den Kopf hinein kommen und was man dagegen tun kann. Musikforscher aus Hannover versuchen nun auch zu erklären, was neuronal im Kopf vor sich geht, wenn eine Melodie in Schleife läuft. Leonie Seng fasst den aktuellen Stand der Forschung zusammen."

Hier zum Nachhören.

 

Dienstag, 10.03.2015 10:27 - Alter: 3 Jahre

Detecting position dependent tremor with the Empirical mode decomposition

Lee, A. & Altenmüller, E.

Journal of Clinical Movement Disorders, 2015, 2

 

Background

Primary bowing tremor (PBT) occurs in violinists in the right bowing-arm and is a highly nonlinear and non-stationary signal. However, Fourier-transform based methods (FFT) make the a priori assumption of linearity and stationarity. We present an interesting case of a violinist with PBT and apply a novel method for nonlinear and non-stationary signals for tremor analysis: the empirical mode decomposition (EMD). We compare the results of FFT and EMD analyses.

Methods

Tremor was measured and quantified in a 50-year-old professional violinist with an accelerometer. Data were analyzed using the EMD, the Hilbert transform, the Hilbert spectrum and the marginal Hilbert spectrum. Findings are compared to the FFT-spectrum and FFT-spectrogram.

Results

We could show that the EMD yields intrinsic mode functions, which represent the tremor and IMFs, which are associated with voluntary movement. The instantaneous frequency and amplitude are obtained. In contrast the low time frequency resolution and the artifacts of voluntary movements are seen in the FFT results.

Conclusions

PBT may present itself as a highly non-stationary and nonlinear phenomenon, which can be accurately analyzed with the EMD, since it gives the instantaneous amplitude and frequency and can identify voluntary from involuntary (tremor) movement.

Zuletzt bearbeitet: 13.12.2017

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